Apparatus for coating a moving web



Dec. 31, 1963 A. M. HALLEY APPARATUS FOR comm; A uovmc was Filed Dec. 11, 1958 INVENTOR Angus Murray Holley 3,116,166 APPARATUS FOR COATING A MOVING WEB Angus Murray Halley, Moseley, Birmingiam, England,

assignor to James Halley & Sons Limited, West Bromwich, England, a British compan Filed Dec. 11, 1958, Ser. No. 779,633 4' Claims. (Cl. 118-68) This invention relates to an improved means for applying wax to the surface of a web of material and more specifically, but not exclusively, has reference to the application of wax impregnated with carbon or other colouring material to a surface of a web of paper, the wax/carbon compound, commonly known as dope, being applied either to the whole of a surface of the web or in the form of panels.

The invention consists of means for applying the wax, usually with a carbon additive, to a surface of a web of material comprising a driven and heated cylinder having a broken surface which is partially immersed in a heated bath of molten wax, a doctor blade for engagement with the surface of the said cylinder, a second cylinder having a resilient surface or surface parts for peripheral contact with the first cylinder, a third driven and heated cylinder adapted to impress the web of material against the resiliently surfaced cylinder so that Wax is transferred from the resilient surface or surface parts onto the Web, and means for cooling the wax which has been applied to the web.

The invention further resides in applying wax, usually with a carbon additive, to a surface of a web of material which comprises the combination of means for abstracting molten wax from a heated bath of wax on the broken surface of a rotating heated cylinder, reducing the wax carried by the said cylinder to a substantially uniform thickness, transferring the wax from the said cylinder to the resilient surface of a second driven cylinder, transfern'ng the wax from the second cylinder onto one side of a web of material being traversed between the sec- ,ond cylinder and a third driven and heated cylinder, and

cooling the wax which has been deposited on the web prior to penetration of the wax to the opposite side of the web.

A preferred means for carrying the present invention into practice as applied to the production of carbon paper will now be described with reference to the accompanying drawing which illustrates in part sectional side elevation a machine in accordance with this invention.

The machine seen in the drawing comprises a heated bath 3 of dope, i.e. wax having a carbon additive. A conventional electrical immersion heater 26 is suitably energized to heat bath 3. A driven cylinder 4, hereinafter referred to as the duct cylinder, is rotatably mounted between the frame standards 5 so as to be peripherally immersed in the bath of dope and in order to maintain the dope in a molten state this cylinder embodies means for heating the cylinder to a temperature of say for example 200 F. The heating means may take the form of means for injecting steam into the hollow interior of the cylinder such as the steam conduit 23. However, since such heating systems are common in the art the present mode of heating does not require description.

The surface of the duct cylinder 4 is broken or mechanically etched to provide a multiplicity of minute recesses therein indicated in exaggerated size in the drawing at 24 by for example cross-cutting the surface of the cylinder in two directions.

The dope which is carried from the bath on the broken surface of the duct cylinder 4 is reduced to a generally uniform layer made up of a small deposit of Wax present nited States Patent in each recess in the cylinder surface by means of a doctor blade 6 bearing on the duct cylinder 4 at a trailing or leading angle.

The molten wax is transferred from the duct cylinder 4 to a second or intermediate cylinder 7, hereinafter referred to as the plate or transfer cylinder, which is rotatably mounted in bearing blocks 8 which are mounted in horizontal slideways a in the frame standards 5 whereby the plate cylinder can be displaced between the inoperative left hand position and operative right hand position shown in the drawings. The bearing blocks 8 are furnished with control means for determining the operational pressure of the plate cylinder upon the neighbouring duct cylinder and the compression cylinder hereinafter referred to. In the illustrated embodiment the control mechanism takes the form of a manually rotatable collar 9 having screw engagement with a short 10 attached to the bearing blocks 8 and a circumferential recess 9a in the collar is engaged by one end of a bell crank lever 12 which is fulcrumed on a part 11 of the frame of the machine so as to be capable of being rocked through the agency of a fluid operated cylinder and piston 13. By this means the pressure of the plate cylinder on its neighbouring duct cylinder and compression cylinder can be adjusted and the plate cylinder can be arranged to be automatically withdrawn from engagement with the neighbouring cylinders by the actuation of the cylinder and piston 13 when the machine is arrested.

Desirably the aforesaid cylinder and piston device 13 is air operated so that in the event of breakage of the web, the web is able to wrap around one or other of the cylinders without quickly straining the machine since the plate cylinder 7 is capable of horizontal displacement against the resistance of the piston and cylinder device.

The periphery of the plate cylinder 7 is of a resilient character, for example, if it is desired to produce a web of material having substantially the whole of one side covered with a wax/carbon deposit then the surface of the plate cylinder is provided with a resilient say rubber covering. Alternatively, if panels of wax/carbon deposit are required the plate cylinder is provided with correspondingly placed resilient pads or the plate cylinder may be built up from a plurality of resilient cylinders mounted in spaced relation on a common shaft.

The plate cylinder 7 is unheated and is allowed to attain its working temperature in operation by the conduction of heat from the adjoining cylinders.

The plate cylinder 7 co-acts with an impression cylinder 14 which is rotatably mounted in bearings 15 supported by the frame standards 5. To admit of the adjustment of the position of the impression cylinder relative to the remaining cylinders the impression cylinder bearings 15 may be mounted in eccentrics 16 furnished with manually operable screw control means 17 for effecting angular displacement of the eccentrics.

The impression cylinder is furnished with means for heating the cylinder in a similar manner to that employed in conjunction with the duct cylinder 4, such as the steam conduit 27.

The duct cylinder 4, the plate cylinder 7 and the impression cylinder 14 are driven at an equal peripheral speed by gearing (not shown).

The web of material to which the wax/carbon compound is to be applied is drawn from a feed roll 21 over an idle roller 22 into the bite between the plate and impression cylinders 7 and 14, and is taken therefrom over a superposed chilling roller 18. The chilling roller is rotatably mounted in hearings in the frame standards 5 and is internally cooled say by introducing coolant in a conventional manner as through conduit 25 and projecting a cold water spray onto the internal wall of the roller preferably at the position Where the web makes initial contact with the roller. By this means the wax is solidified on the web. In order to prevent penetration of the wax to the opposite side of the web the chilling roller ismounted as close to the cylinder as is practicable.

The web is drawn from the chilling cylinder over an idle roller 19 to a rewinding roller 20.

*It is found that the above described apparatus admits of the application to the web of a very thin film of wax/carbon compound and is ideally suited for the production at high speed of so called one time carbon paper.

I claim:

1. Apparatus for applying a coating of Wax-like material to the surface of a moving web comprising means providing a bathof said material, means for heating said material to a fluent condition, a rotatable duct cylinder having a portion of its surface immersed in said heated fluent material, the surface of said cylinder having a multiplicity of minute material pick-up recesses therein, a doctor blade engaging the surface of said duct cylinder for removing from said cylinder surface substantially all of said material except that filling the recesses therein, means for heating said duct cylinder, a resilient surfaced rotating material transfer cylinder in direct rolling contact with the surface of said duct cylinder adapted to continuously remove said material from the surface recesses of said duct cylinder in small deposits which are inverted during transfer to the surface of said transfer cylinder, means for passing the web to be coated in direct contact over the portion of said transfer cylinder surface bearing said coating material so that said small deposits are again inverted during transfer from the transfer cylinder to the web surface, a rotatable impression cyiinder located to directly engage the web on the opposite side from that receiving the coating fromthe transfer cylinder and urge the web under pressure into operative contact with said transfer cylinder, means for heating said impression cylinder, and means for cooling the coated web.

2. In the coating apparatus defined in claim 1, said cooling means comprising a coating chilling roller over which the uncoated surface of the coated web passes after leaving the pass between the transfer and impression cylinders.

3. In the coating apparatus defined in claim 1, means for adjusting said transfer cylinder relative to both the duct cylinder and the impression cylinder in direct contact therewith, and means for independently adjusting the impression cylinder pressure on the transfer cylinder.

4. In the coating apparatus defined in claim 3, said firstnamed adjusting means comprising a pneumatic motor actuated mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 596,564 Allen Jan. 4, 1898 1,122,473 Butler Dec. 29, 1914 1,902,264 Rector Mar. 21, 1933 1,911,592 Supligeau et al May 30, 1933 1,914,488 Custers June 28, 1933 2,108,389 Paul Feb. 15, 1938 2,249,088 Murray July 15, 1941 2,396,946 Grupe Mar. 19, 1946 2,681,636 Fridolph June 22, 1954 2,781,278 Harmon Feb. 12, 1957 2,830,555 Barrett Apr. 15, 1958 2,874,674 Hornbostel Feb. 24, 1959 FOREIGN PATENTS 210,350 Switzerland Sept. 16, 1940 149,791 Great Britain Aug. 26, 1920 

1. APPARATUS FOR APPLYING A COATING OF WAX-LIKE MATERIAL TO THE SURFACE OF A MOVING WEB COMPRISING MEANS PROVIDING A BATH OF SAID MATERIAL, MEANS FOR HEATING SAID MATERIAL TO A FLUENT CONDITION, A ROTATABLE DUCT CYLINDER HAVING A PORTION OF ITS SURFACE IMMERSED IN SAID HEATED FLUENT MATERIAL, THE SURFACE OF SAID CYLINDER HAVING A MULTIPLICITY OF MINUTE MATERIAL PICK-UP RECESSES THEREIN, A DOCTOR BLADE ENGAGING THE SURFACE OF SAID DUCT CYLINDER FOR REMOVING FROM SAID CYLINDER SURFACE SUBSTANTIALLY ALL OF SAID MATERIAL EXCEPT THAT FILLING THE RECESSES THEREIN, MEANS FOR HEATING SAID DUCT CYLINDER, A RESILIENT SURFACED ROTATING MATERIAL TRANSFER CYLINDER IN DIRECT ROLLING CONTACT WITH THE SURFACE OF SAID DUCT CYLINDER ADAPTED TO CONTINUOUSLY REMOVE SAID MATERIAL FROM THE SURFACE RECESSES OF SAID DUCT CYLINDER IN SMALL DEPOSITS WHICH ARE INVERTED DURING TRANSFER TO THE SURFACE OF SAID TRANSFER CYLINDER, MEANS FOR PASSING THE WEB TO BE COATED IN DIRECT CONTACT OVER THE PORTION OF SAID TRANSFER CYLINDER SURFACE BEARING SAID COATING MATERIAL SO THAT SAID SMALL DEPOSITS ARE AGAIN INVERTED DURING TRANSFER FROM THE TRANSFER CYLINDER TO THE WEB SURFACE, A ROTATABLE IMPRESSION CYLINDER LOCATED TO DIRECTLY ENGAGE THE WEB ON THE OPPOSITE SIDE FROM THAT RECEIVING THE COATING FROM THE TRANSFER CYLINDER AND URGE 